For dust particles, I use compressed air.
For things not able to remove with air… hmmm… be carefull you can destroy the reflector. Normally I use clean cloth, the similar to clean LCD and displays
A few minutes work with some 80 grit carbide sandpaper, and that annoying fingerprint will be history!
I usually use a piece of chamois leather, the same stuff I clean my camera lenses with. Don’t however, try to use any kind of cleaning fluid.
Lens cleaning solution might be fine for optics but I don’t recommend it for the reflectors. Also, use a blower-brush to gently blow away any dust particles on the reflector before wiping it (gently) 
Use as little force as possible always-and don’t rush it!
Buy a new reflector or send the light back or complain to the manufacturer or complain to the supplier and manufacturer… (sorry, decisions are not my thing at the moment lol )
Microfiber towel & lcd - lens cleaning fluid
I still think that the recommendations over at CPF by vinhnguyen54 are the best. Shake the reflector in warm water with soap, rinse with clear water, then blow it dry with compressed air. If that doesnt work, lick it, rinse it with clear water, then blow it dry with compressed air.
Works.
wait, you guys are SERIOUS about the licking?
you gotta get 300% of your recommended daily intake of Lead somehow
Yup: http://www.candlepowerforums.com/vb/showthread.php?330011-vinhnguyen54-How-Clean-A-P60-Reflector
Hahaha! NightCrawl, thanks. It sounds sensible. I’ll try it soon.
… stickytape,
purple nitrile glove and dishwashing soap and hot water.
no scratches. the glove keeps it from scratching. i did this to a reflector once with my finger and soap and it scratched it some but with the glove it doesnt.
no water spots though i am really careful to shake/blow with compressed air while the reflector is still hot.
Brian
To not get any water spots do the last rinse with pharmacy bought distilled water, it air dries spot free!
Alex, I was thinking the same thing (since I have no compressed air). Thanks.
Not always, if it has picked up sediment as your using it, the sediment will redeposit as the water dries. You can drive yourself mad trying to wash away that sediment, even with repeated washings
Besides, the best use of distilled water is for drinking, it has superior taste to most any water out there
Well, you either really have to know what you are doing or that was a joke. Drinking distilled water can be dangerous.
I think that distilled water will “soak up” the minerals from your body, not sure if it’s a good idea to ingest
why in the world would distilled water be dangerous?
Wow! thanks for all the ideas.
I will narrow it down & post how it does. If you dont have a small air compressor a can of that compressed air for dusting computers works well too.
Just be very careful that no liquid from the compressed air can gets on the reflector, it will leave spots